add PRESUBMIT for native_client_sdk.

native_client_sdk/src/build_tools/build_utils.py

 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Small utility library of python functions used by the various package
 installers.
 """
 
 import datetime
 import errno
@@ skipping 168 matching lines @@
 
   This file either needs to be in either a subversion repository or
   a git repository that is sync'd to a subversion repository using git-svn.'''
   run_path = os.path.dirname(os.path.abspath(__file__))
   p = subprocess.Popen('svn info', shell=True, stdout=subprocess.PIPE,
                        cwd=run_path)
   if p.wait() != 0:
     p = subprocess.Popen('git svn info', shell=True, stdout=subprocess.PIPE,
                          cwd=run_path)
     if p.wait() != 0:
-      raise AssertionError('Cannot determine SVN revision of this repository');
+      raise AssertionError('Cannot determine SVN revision of this repository')
 
   svn_info = p.communicate()[0]
   m = re.search('Revision: ([0-9]+)', svn_info)
   if m:
     return int(m.group(1))
   else:
     raise AssertionError('Cannot extract revision number from svn info')
 
 
 def VersionString():
@@ skipping 96 matching lines @@
   Args:
     dir: The directory to clean
   '''
   if sys.platform != 'win32':
     shutil.rmtree(dir, ignore_errors=True)
   else:
     # Intentionally ignore return value since a directory might be in use.
     subprocess.call(['rmdir', '/Q', '/S', dir],
                     env=os.environ.copy(),
                     shell=True)